json: fix uninitialized variables

json.c: In function ‘json_parse_ex’:
json.c:260:30: warning: ‘string_length’ may be used uninitialized in this function [-Wmaybe-uninitialized]
json.c:358:16: warning: ‘string’ may be used uninitialized in this function [-Wmaybe-uninitialized]
skype: support setting mood text

Requested by martinc on IRC.
skype: make checkpatch happy again (cosmetics)
skype: remove unused build system targets, references to git
Merge from vmiklos.