added the function extract_waveunit to find out which unit was used in a FITS header to measure wave lengths
typo
save the wavelength unit in the header in the key WAVEUNIT if it could be read
set the WAVEUNIT value actually in the fits module, not in file_tools
Add small doctest section
Guide update
Merge branch 'staging' into extract_waveunit
Merge branch 'staging' of https://github.com/sunpy/sunpy into extract_waveunit
support more formats for detecting the waveunit
detect_waveunit: support all exponents from -1 to -24
Merge branch '0.3' of https://github.com/sunpy/sunpy into extract_waveunit

Conflicts:
	sunpy/io/fits.py
added example in documentation of extract_waveunit
extend fits.get_header documentation
say that the key WAVEUNIT is written and contains the wavelength unit which is used
to measure the wavelength (used in the value of WAVELNTH).
Make file name parsing more flexible.

Now the file format can be specified per instrument as opposed to for the full archive.
This can be useful as e.g. BINGO-8BIT has a slightly different format.
good bye make_map
fixed example of extract_waveunit
strip out wheel command
yml patch
upgrade flag
Merge remote-tracking branch 'upstream/0.3' into 0.3_wheels

Conflicts:
	.travis.yml