Applied fix to asyncmodel, minor changes to pref util & doc changes

[Rea][Fix]: AsyncModel - Removed some clutter comments. Fixed a
potential issue with send(int,Bundle) not casting before moving on
(would give a stack overflow)
[Mod]: Changed the first run preference of Pref Util; this will
technically cause all current settings to reset again but, considering
the lack of user set preferences, this is a non-issue.
[Doc]: Added todo in the formatter
[Doc]: Update comment in the preference info
Added Abstract XmlParser & SimpleHttpRequest from CareerStack

[Add]: AbstractXmlParser is a base for simple xml parsing. Can be paused
and resumed (if correctly extended).
[Add]: AbstractSimpleHttpRequest is a base for the entire request mark
the request building. Can be cancelled.
Extended abstract parser & request into YahooApi & updated asyncmodel

[Mod]: YahooApiCurrencyRequest now extends AbstractSimpleHttpRequest,
making it safer and tidier.
[Mod]: YahooApiCurrencyXmlParser now extends AbstractXmlParser, making
it cleaner and mmore useful.
[Doc][Mod]: The async model now implements the updated interface from
AbstractSimpleHttpRequest and has better comments to explain how it
works.
Moved strings from currency_codes to & added new val for settings

[Ref]: Moved currency string names to strings.xml
[Mod]: Added strings for various times for settings
[Add]: Added the list of times parallel to those strings
Added settings fragment, various update times, & ToastManager 

[Add]: Added ConfirmationDialogFragment from CareerStack; rotation
resistent, fragment + activity compatible dialog.
[Add]: ToastManager was added from CareerStack; manages toast.

[Add]: Added SettingsFragment using PreferenceFragment library
(https://github.com/kolavar/android-support-v4-preferencefragment). This
addresses some issues in #1 including:
-Software Version number
-10 different update times (5 min, 15 min, 30, 1 hr, 2hr, 6hr, 12hr,
24hr, 2 days, 1 week)
&
-Reset all settings
Added better support for diff sizes & mild redesigns - #5

[Add]: Added limits to remove flag image on smaller screens; default
disables, w300dp enables.
[Mod]: MainFragment now ensures to check it's view is visible (required
for backstack). Additionally, it adds and removes its model based on
view not fragment.
[Mod][Ref]: Moved main input views into their own view stub & made the
view hidden resistent. Additionally, removed spacing from list and set
it only on inputs
[Add]: Added layout for large sizes (540dp). Minimal testing thus far.
Set Main to handle multiple fragments 

[Mod]: MainActivity now handles the loading of both Settings & Main
fragments. Including the hiding of settings and managament of the action
bar button. This allows settings to be accessible as per issue #1

[Mod]: Updated version number to prepare for next potential release
Fixed small screen support on 2.3.3 & changed tablet screen layout

[Add][Mod][Ref]: dp based screen support won't work on pre-3.0 so thus
added limits to:
+ values-small-land
+ values-normal
+ values-large
+ values-xlarge
which all point to/duplicate the values in w320dp (new width from
w300dp)

[Mod][Ref]: Changed the "wide" tablet mode to be for 720dp. This means a
7in tablet will only use it in landscape, not portrait (which looks too
crowded). Additionally, added padding to the list in portrait mode.
[Mod][Add]: Updated README to reflect additions & added screenshots

These include the screenshots for tablet/small mode & the use of the
PreferenceFragment library.