build: Remove grlpls double-check

https://bugzilla.gnome.org/show_bug.cgi?id=727901
filesystem: Disable plugin if grlpls isn't present

https://bugzilla.gnome.org/show_bug.cgi?id=727901
magnatune: Fix build if grlnet isn't present

https://bugzilla.gnome.org/show_bug.cgi?id=727901
lua-factory: Fix build when grlnet or json-glib is missing

https://bugzilla.gnome.org/show_bug.cgi?id=727901
tmdb: Fix build when grlnet is missing

https://bugzilla.gnome.org/show_bug.cgi?id=727901
bookmarks: Use gom to access the database

Instead of SQLite directly.

gom is currently available at:
https://github.com/chergert/gom/

Fixes:
- No injection security holes
- Easy DB extension

Functional changes:
- Boxes don't have a childcount anymore
- Query has a different syntax which more closely matches
  the database names (as opposed to the undiscoverable names used
  in the queries)
- Orphans are cleaned up on startup rather than when removing items

https://bugzilla.gnome.org/show_bug.cgi?id=673912
bookmarks: Remove unused struct member

https://bugzilla.gnome.org/show_bug.cgi?id=673912
bookmarks: Don't use g_strconcat() to build paths

Use g_build_filename() instead.

https://bugzilla.gnome.org/show_bug.cgi?id=673912
bookmarks: Also save thumbnail URL

https://bugzilla.gnome.org/show_bug.cgi?id=673912
lua-factory: Ensure that fetches error out on non-UTF-8

This makes sure that we do not pass binary data as a result
for lua fetch operations.

https://bugzilla.gnome.org/show_bug.cgi?id=728525
lua-factory: Split out GrlNetWc option setting

We'll need this shortly.

https://bugzilla.gnome.org/show_bug.cgi?id=728525
lua-factory: Simplify initial variable state

That way, the compiler can actually tell us when something is
not initialised when we used it.

https://bugzilla.gnome.org/show_bug.cgi?id=728525
lua-factory: Remove unneeded temporary name for struct

https://bugzilla.gnome.org/show_bug.cgi?id=728525
lua-factory: Add grl.unzip library function

Script developers can use this to fetch a zip file, and extract
particular files inside that zip file.

This also adds a libarchive dependency for the lua-factory plugin.

https://bugzilla.gnome.org/show_bug.cgi?id=728525
lua-factory: Document OperationSpec struct

https://bugzilla.gnome.org/show_bug.cgi?id=728882
lua-factory: Add string member to OperationSpec struct

To be used to cache operation parameters.

https://bugzilla.gnome.org/show_bug.cgi?id=728882
lua-factory: Add more keys to grl.get_options()

Make it possible to get the query/search strings, or the media ID
for the operation, as well as the operation type.

This is useful when the entry point needs to launch an async operation
to cache a manifest for example.

https://bugzilla.gnome.org/show_bug.cgi?id=728882
lua-factory: Fix garbage after escaped text in grl.unescape()

grl.unescape('&quot;Look at Me&quot;')
would give back:
"Look at Me"t Me&quot;
instead of:
"Look at Me"

Don't forget to terminate the copied string when we've unescaped.

https://bugzilla.gnome.org/show_bug.cgi?id=729649
optical-media: Add some more debug

https://bugzilla.gnome.org/show_bug.cgi?id=729704
optical-media: Fix physical optical drives being ignored

Better when tested right? Don't ignore all the drives...

https://bugzilla.gnome.org/show_bug.cgi?id=729704