don't require context when it's not necessary

this commit should not include any substantive changes, as in all of
these cases, the passed context parameter is never actually being used.
Most of these are simply leftover from previous versions when they were
used.

git-svn-id: https://android.svn.wordpress.org/trunk@949 a6565c4b-a94d-4d28-bb26-aa9e5ab542c0
add new methods for setting currentBlog

the goal here is to move away from quite so many places in the code
directly manipulating the global state.  This will allow for some
additional optimizations down the road.

git-svn-id: https://android.svn.wordpress.org/trunk@950 a6565c4b-a94d-4d28-bb26-aa9e5ab542c0