Show full path of library in status bar

Show full path of library under mouse in status bar when
switching/renaming/deleting libraries via the calibre library button.
Fixes #1224925 [[Enhancement]Show full path for libraries](https://bugs.launchpad.net/calibre/+bug/1224925)
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Ignore errors in third party UI plugins during genesis
In the comments editor, permit insertion of references to images on the 'net (<img ...>) as well as links (<a ...>).
Comments editor: Allow treating arbitrary URLs as images

Merge branch 'master' of https://github.com/cbhaley/calibre
Allow colons in identifier values

Fixes #1224885 [<dc:identifier opf:scheme="URI"> and semicolon #2](https://bugs.launchpad.net/calibre/+bug/1224885)
Update Politika
Fix #1225552 [Windows portable executable file description should be "Calibre"](https://bugs.launchpad.net/calibre/+bug/1225552)
Book list should track edit metadata dialog

Fix regression in 1.3 that caused the book list to not track the
ecurrent book when using Next/Previous in the edit metadata dialog.
Fix #1225499 [non translatable "completed" for completed jobs](https://bugs.launchpad.net/calibre/+bug/1225499)
Have metadata.book.set_all_user_metadata actually set the metadata, not merge it.
Merge pull request #84 from cbhaley/master

Have metadata.book.set_all_user_metadata actually set the metadata, not ...
Conversion: Handle shorthand CSS properties

Conversion: Fix bugs in the handling of shorthand CSS properties
such as font or border, which could cause some properties to
not be resolved correctly during conversion.
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pep8
pep8
pep8
Use shorthand properties for margin, border and padding
Merge branch 'normalize'

EPUB/AZX3 Output: Use shorthand forms for margin, padding and
border CSS properties

Conversion: Fix a bug that could cause incorrect border values to be
used when cascading, shorthand border CSS is present.
When copying books from library A to library B, check that B contains the necessary custom columns. If not, tell the user and allow them to create any non-conflicting columns. Inform them about conflicting columns.