[Doc]: Corrected some documentation typos & short-sights 

Includes the default time in the doc.
[Fix]: MainActivity backbutton press to give consistent results

The hardware button was not giving the same results as actionbar; forgot
to called onSupportNavigateUp() in onBackPressed()
Improved thread safety in helper, updated model methods to close

[Doc][Rea]: Improved readablity in the open helper, rearranged tags,
etc.
[Fix]: The returning of helpers is now synch'ed & the list of helpers
made final (we don't intend to let anyone modify it)
[Fix]: Read/write methods now close in the finally{} tag
Added gson (2.3) & AbstractJsonParser for parsing json response 

See issue #2

[Add]: gson 2.3 jar library + the source, documentation, & properties
files for easy of use in Eclipse
[Add]: AbstractJsonParser provides a slightly easier way to use Json
Reader and a means to pause/resume (if implemented).
Moved CodeRatePair,tweaked Xml parser,add JSON parser & fix request

See issue #2

[Ref]: Moved CodeRatePair to its own class. Additionally, added the
method to split the id tag (e.g. USDEUR) to the code pair object.
[Add]: Added the json parser to parse the json response and return the
results
[Doc]: Added more explicity documentation to the xml parser about the
expected content

[Fix]: Fixed the json option in the yahoo request. It would have never
triggered in its former state; I had never finished it. Whoops!

Then again, I only just added the json so, no harm?
Add Json parsing pref & implemented it in async model + minor fix

See issue #2

[Mod]: Added JSON preference defaults (true)
[Fix]: Ensured only one request can run at a time in model.
[Mod]: Added Json preference to model allow it to set the request to
JSON and parse it.
Added Json parsing setting & ability to launch "More Apps" intent

[Add]: Added MarketIntent utility which allows for more robust launching
of market intents
[Mod]: Added strings for use in settings fragment
[Mod]: "Use JSON" preference & "More Apps" added to settings frag.

This should close issues #1 and #2
Tweaked the colours of the results rows & added higher res icon

[Mod]: Removed colours for odd numbers, added a different blue for evens
[Add]: Larger resolution launcher icon for tablets and the like.
[Mod]: Updated versionCode/name for next release