Adding proper watch support and implements its dual, the unwatch command

This commit enables users to use the following pattern:

   WATCH
   GET
   MULTI
   EXEC/DISCARD

The old behavior have been kept intact, i.e., the multi function
continues to accept a list of keys to watch prior issuing the watch
command, although I believe this use should be deprecated.

The watch command may also be used standalone. In this case, users
should make use of the watch command to clear the `inTransaction'
state.

Some examples (the following assumes inlineCallbacks):

  # 1. Using watch/unwatch
  tx = yield conn.watch(...)
  ...
  yield tx.unwatch()

  # 2. Using watch/multi
  tx = yield conn.watch(...)
  ...
  yield tx.multi()
  ...
  yield tx.commit()

  # 3. Using watch only
  tx = yield conn.multi(...)
  ...
  yield tx.commit()

  # 4. All together:
  tx = yield conn.watch(...)
  ...
  yield tx.multi()
  ...
  yield tx.unwatch() # this will not clear
                     # the `inTransaction` state
  ...
  yield tx.commit()
Merge pull request #33 from dgvncsz0f/master

Adding proper watch support and implements its dual, the unwatch command
moved travis badge up
dealing with some edge cases and documenting the new WATCH functionality

This patch deals with the following scenarios, which would ended up
cleaning the inTransaction prematurely:

1. UNWATCH after MULTI

  t = multi
  t.unwatch

2. WATCH, MULTI (with keys)

  t = watch
  t.multi("foobar")
  t.unwatch

3 . MULTI + WATCH

  t = multi
  t.watch   # this is invalid, but
              will change the _unwatch_cc
              to a function that would clear
              the inTransaction state

I've also dropped a couple more tests, notably testing WATCH with ConnectionPool.
Merge pull request #34 from dgvncsz0f/master

dealing with some edge cases and documenting the new WATCH functionality
Redis 2.6 Lua scripting support
Merge pull request #35 from jeethu/scripting

Redis 2.6 Lua scripting support
version 1.0
version 1.0
changed lpush and rpush to cope with passing python lists around to be appended
Merge branch 'master' of github.com:fiorix/txredisapi