Merge pull request #33 from jcristovao/master

Replaced MonadCatchIO with exceptions and relaxed some dependencies
keep track of http history in WDSession
add helper for dumping session http history
version bump
Merge pull request #35 from zerobuzz/keep-http-history+1

Keep http history+1
introduce flag for session history tracking; disable by default.
rm trailing whitespace
Merge pull request #36 from zerobuzz/keep-http-history+2

Keep http history+2
use http-client instead of HTTP, for conn pooling
close http manager when closing session
Merge pull request #41 from echaozh/use-http-client

Use http-client instead of HTTP, for conn pooling
update dumpSessionHistory documentation
WDSession/WDConfig overhaul
more control over http requests to the webdriver server
refactored internals
minor change in handleJSONErr
Merge pull request #43 from echaozh/http-config

more control over http requests to the webdriver server
Add a basic usage guide to README
typo in README
remove ReaderT from monad stack; heavy rework of WDConfig and WDSession; runSession no longer autocloses sessions; closeSession no longer closes Manager