talkatu/talkatu

ebabd7682683
Update TalkatuMessage:id to be a string.

Many modern protocols are using uuids as id's and forcing that into a uint64 is
going to lead to collisions. So instead just use a string which should work for
everything.

Testing Done:
Ran the demo and unit tests.

Reviewed at https://reviews.imfreedom.org/r/879/
demo/data/demo.ui
demo/talkatudemo.c
demo/talkatudemowindow.c
talkatu/data/attachmentdialog.ui
talkatu/data/attachmentpreview.ui
talkatu/data/editor.ui
talkatu/data/historyrow.ui
talkatu/data/linkdialog.ui
talkatu/data/messageactions.ui
talkatu/data/toolbar.ui
talkatu/talkatuactiongroup.c
talkatu/talkatuattachment.c
talkatu/talkatuattachmentdialog.c
talkatu/talkatuattachmentpreview.c
talkatu/talkatubuffer.c
talkatu/talkatucodeset.c
talkatu/talkatucore.c
talkatu/talkatueditor.c
talkatu/talkatuhistoryrow.c
talkatu/talkatuhistory.c
talkatu/talkatuhtmlbuffer.c
talkatu/talkatuhtmlrenderer.c
talkatu/talkatuinput.c
talkatu/talkatulinkdialog.c
talkatu/talkatumarkdownbuffer.c
talkatu/talkatumarkup.c
talkatu/talkatumenutoolbutton.c
talkatu/talkatumessageactions.c
talkatu/talkatumessage.c
talkatu/talkatuscrolledwindow.c
talkatu/talkatusimpleattachment.c
talkatu/talkatutag.c
talkatu/talkatutagtable.c
talkatu/talkatutoolbar.c
talkatu/talkatutooldrawer.c
talkatu/talkatutypinglabel.c
talkatu/talkatuview.c
talkatu/talkatuwholebuffer.c
talkatu/tests/talkatutestactiongroup.c
talkatu/tests/talkatutesthtmlserialization.c