Whoops.  Bad file name on "Android Activities".
Fixed naming of the android activities lab.
Add reading on anonymous inner classes.
Add reading on stacks.
Add reading on linear structures.
Add reading on queues.
Add start of reading on loop invariants.
Add reading on priority queues.
Add reading on Quicksort.
Add reading on search.
Revision of lab on android activities.
Fix bug in the reading on loop invariants.
Add lab on anonymous inner classes.
Update android labs.
Add lab on array-based queues.
Add lab on stacks.
Add lab on binary search trees.
Add lab on Java from the command line.
Add lab on hash tables.
Add lab on heaps.