Fix issues

[meggart]

This should fix #61 by showing a Progress meter of unknown length if length is unknown and #58 by throwing a warning when no common axes are found in 2 cubes

[meggart]

And adds a hash function for CubeAxis, fixing #60

[codecov]

Codecov Report

Merging #62 (357a474) into master (4de682d) will decrease coverage by 0.15%.
The diff coverage is 12.50%.

@@            Coverage Diff             @@
##           master      #62      +/-   ##
==========================================
- Coverage   55.56%   55.41%   -0.16%     
==========================================
  Files          13       13              
  Lines        1544     1550       +6     
==========================================
+ Hits          858      859       +1     
- Misses        686      691       +5     

Impacted Files	Coverage Δ
src/DAT/dciterators.jl	0.00% <0.00%> (ø)
src/DAT/tablestats.jl	0.00% <0.00%> (ø)
src/Cubes/Axes.jl	60.66% <100.00%> (+0.26%)	⬆️

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[coveralls]

Pull Request Test Coverage Report for Build 832207247

• 0 of 7 (0.0%) changed or added relevant lines in 2 files are covered.
• 24 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.3%) to 55.297%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/DAT/dciterators.jl	0	2	0.0%
src/DAT/tablestats.jl	0	5	0.0%

Files with Coverage Reduction	New Missed Lines	%
src/Cubes/Axes.jl	24	60.14%

Totals
Change from base Build 813326560:	-0.3%
Covered Lines:	856
Relevant Lines:	1548

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💛 - Coveralls