Windows bug fixes, more robust image cropping, better text output

Fixes #369 (Windows absolute file path calculation)
Fixes #374 (better text output than simply 'cropping images')
Removes pointless thumbnails folder from history dir (#373)
Crop task copes with differences in height and now width (#296)
history image filenames now end in 'base' (#368)
#390 added in better file locating too, so Wraith now detects both .yml and .yaml files automatically.