ENH: Add class for reading unformatted Fortran files
Change fortran_file/FortranFile API to match suggestions.

fortran module is now hidden
Corrected tests and doctest
DOC: Fixup documentation on FortranFile

Fix spelling mistakes
Move documentation from hidden module to class
Limit line widths
Warn if using dtypes which are not unsigned for record markers
MAINT: minor performance improvement

Merge two loops and move invariant of switch case out of inner loop.
Improves performance by 5% - 10% depending on the order.
MAINT: tell compiler that edge interpolation is less likely

This should be true for most cases where performance is relevant.
Improves performance by about 5% on images > (500, 500) with order three.
MAINT: add map_coordinate tests with non-continous arrays
ENH: unstable beginning of expm_action implementation
ENH: matrix power operator
ENH: expm_action implemented and tested
MAINT: move the main function to the beginning of the module
BUG: mired in scipy/numpy ndarray/matrix/sparse hell
MAINT: final commit before ripping out the buggy attempts to support sparse matrices
ENH: expm_action for sparse matrices added and tested
MAINT: move compatibility functions to the beginning of the module where they may be easily seen and replaced when they become obsolete in the future
ENH: expm_action over an interval of evenly spaced time points
BUG: still buggy for intervals for which many time points were requested relative to the number of desired rescalings
ENH: Add canonical representation for lti objects
BUG: expm_action complicated case now works under certain restricted conditions using some unnecessarily inefficient lines
BUG: the time interval code seems to work now
TST: expm_action tests and fix an inefficiency