check if loop mount is possible

if not abort gracefully with an explanation
(10x to Bucciarati and sdonk)
fixed versioning and extras reorganization
fixes to gtk tray program
fix to engrave usage of qrencode
more post-hooks documentation and second argument passed with mountpoint
Detect non-partition swaps
Support encrypted swap
Support multiple swaps
Support encrypted swaps
Change default cipher specification

new default is "aes-xts-plain64:sha256"
manpage now includes note on how to tune it
fixes #102
Merge pull request #101 from hellekin/swap

Better support for multiple swap partitions, avoids warning if swap is encrypted.
correct documentation on -s option

somewhere mentioned as --size, but the option is really just -s
fixes #100
sanitized the way key filenames are set

there was some inconsistency in the way load_keys was accepting
different parameters or guessing from the tomb filename.

fixes #98
Resize now appends directly to tomb file

this avoids creating a delta file in ram, filling it eventually.
fixes #99
release documentation updates
fixed correct handling and deletion of keys when taken from stdin
fixes issue #74 for the new directory structure
documentation update for minor bugfix release
another fix to key handling

ultimately removing the case in which we guess if the key is near
the tomb: that is not anymore in documentation and we stop encouraging
to keep the key near the tomb.
documentation for a new minor release