ERR/DEPR: Fix quantile error message / remove percentile_width

[sinhrks]

Currently, error is raised from numpy and incorrect for pandas

s = pd.Series([1, 2, 3])
s.quantile(2)
#   File ".../numpy/lib/function_base.py", line 3078, in _percentile
#     raise ValueError("Percentiles must be in the range [0,100]")
# ValueError: Percentiles must be in the range [0,100]

describe using percentiles option outputs better error message, but not check lower limit.

# OK
s.describe(percentiles=[2])
# Traceback (most recent call last):
#   File "pandas/core/generic.py", line 4167, in describe
#    raise ValueError(msg.format(list(percentiles)))
# ValueError: percentiles should all be in the interval [0, 1]. Try [0.02] instead.

# NG
s.describe(percentiles=[-2])
#   File ".../numpy/lib/function_base.py", line 3078, in _percentile
#     raise ValueError("Percentiles must be in the range [0,100]")
# ValueError: Percentiles must be in the range [0,100]

This PR fix both error messages. Also, remove deprecated percentile_width option in describe.

[sinhrks]

Ah, found an existing bug which drops Series.name. Fixed in the same PR.

# current master
pd.Series([1, 2, 3], name='x').quantile([0.5])
# 0.5    2
# dtype: float64

[jreback]

thanks!