Added the remove_file() API function.

This function is added to provide a standard way of removing previously
generated files within a project target directory, both when in form-based
as well as in Quickstart mode. It automatically performs some safety checks
and lets the underlying initialization process fail if a file cannot
be removed, which should be the default anyway because otherwise that would
mean that the project cannot be initialized as the init code author intended.
Therefore, by using this function the call site becomes cleaner as the error
handling code can be omitted.

VERSION

@@ -1 +1 @@
-1.7.4-dev
+1.8.0-dev

libinit.sh

@@ -5572,3 +5572,97 @@ function proceed_next_level() {
 
   source "$next_lvl_script";
 }
+
+# [API function]
+# Removes a file or directory within the project target directory.
+#
+# The specified file path argument is interpreted as relative to the
+# project target directory.
+#
+# When in regular (form-based) application mode, the project target directory must
+# have already been created by means of the project_init_copy() function before a file
+# can be removed.
+# 
+# When in Quickstart mode, the project target directory is the underlying Quickstart
+# current working directory, i.e. where the Quickstart was initiated. If the specified
+# file or directory does not exist, or if it was not previously created by the same
+# Quickstart function, then this function will cause the application to cancel the
+# entire Quickstart operation.
+#
+# Since:
+# 1.8.0
+#
+# Args:
+# $1 - The relative path of the file or directory to remove in the project
+#      target directory. This is a mandatory argument.
+#
+# Examples:
+# remove_file "subdirA/the_src_file.txt";
+#
+function remove_file() {
+  local arg_target="$1";
+  if [ -z "$arg_target" ]; then
+    _make_func_hl "remove_file";
+    logE "Programming error: Illegal function call:";
+    logE "at: '${BASH_SOURCE[1]}' (line ${BASH_LINENO[0]})";
+    failure "Programming error: Invalid call to ${HYPERLINK_VALUE} function: " \
+            "No file argument specified";
+  fi
+  if _is_absolute_path "$arg_target"; then
+    _make_func_hl "remove_file";
+    logE "Programming error: Illegal argument '${arg_target}'";
+    logE "at: '${BASH_SOURCE[1]}' (line ${BASH_LINENO[0]})";
+    failure "Programming error: Invalid call to ${HYPERLINK_VALUE} function: " \
+            "The file argument must not be absolute";
+  fi
+
+  local target_file="";
+  if [[ $PROJECT_INIT_QUICKSTART_REQUESTED == true ]]; then
+    target_file="${_PROJECT_INIT_QUICKSTART_OUTPUT_DIR}/${arg_target}";
+    if ! [ -e "$target_file" ]; then
+      logW "Cannot remove file '${arg_target}'";
+      logW "File or directory does not exist:";
+      logW "at: '${target_file}'";
+      _cancel_quickstart $EXIT_FAILURE;
+    fi
+    if ! _array_contains "$target_file" "${CACHE_ALL_FILES[@]}"; then
+      _make_func_hl "remove_file";
+      logW "Cannot remove file '${arg_target}'";
+      logW "A file may only be removed by the ${HYPERLINK_VALUE} function if it was";
+      logW "previously generated by a Quickstart function";
+      _cancel_quickstart $EXIT_FAILURE;
+    fi
+  else
+    if [[ ${_FLAG_PROJECT_FILES_COPIED} == false ]]; then
+      _make_func_hl "remove_file";
+      local _hl_remove_file="$HYPERLINK_VALUE";
+      _make_func_hl "project_init_copy";
+      local _hl_pic="$HYPERLINK_VALUE";
+      logE "Programming error in init script:";
+      logE "at: '${BASH_SOURCE[1]}' (line ${BASH_LINENO[0]})";
+      failure "Missing call to project_init_copy() function:"                              \
+              "When calling the ${_hl_remove_file} function, the target project directory" \
+              "must already be created. "                                                  \
+              "Make sure you first call the ${_hl_pic} function in your init script";
+    fi
+    target_file="${var_project_dir}/${arg_target}";
+  fi
+  local file_type="file";
+  if [ -d "$target_file" ]; then
+    file_type="directory";
+    rm -r "$target_file" 2>/dev/null;
+  else
+    rm "$target_file" 2>/dev/null;
+  fi
+
+  local cmd_rm_stat=$?;
+  if (( cmd_rm_stat != 0 )); then
+    logE "Failed to remove ${file_type} inside project directory";
+    logE "Command rm returned non-zero exit status ${cmd_rm_stat}";
+    logE "File: '${arg_target}'";
+    _cancel_quickstart $EXIT_FAILURE;
+    failure "Failed to remove source files";
+  fi
+  find_all_files;
+  return 0;
+}