added caches for favourites, home, list, and user methods
set the correct variable
add caching for search
don't try to write the cache file if directory is unwritable
Merge branch 'master' of https://github.com/levymetal/tweetledee into levymetal-master

Conflicts:
	tweetledee/favoritesjson_nocache.php
	tweetledee/favoritesjson_pp_nocache.php
	tweetledee/favoritesrss_nocache.php
	tweetledee/homejson_nocache.php
	tweetledee/homejson_pp_nocache.php
	tweetledee/homerss_nocache.php
	tweetledee/listsjson_nocache.php
	tweetledee/listsjson_pp_nocache.php
	tweetledee/listsrss_nocache.php
	tweetledee/userjson_nocache.php
	tweetledee/userjson_pp_nocache.php
	tweetledee/userrss_nocache.php