First set of changes.
Simplified use of SimpleCrypt
* Changed allocation of SimpleCrypt from heap to stack. This
  simplifies its use a little as we don't need to keep track
  of construction and deletion.
* Removed manual deletion of QNAM as it's parent is already set
  and Qt wuill take of deleting children when parent is deleted.
* Added a few string contants which are being used repeatedly.
* Added a helper function for generating the key to be used for
  encrypting/decrypting stored tokens.
Second set of changes
Minor code cleanup

* Simplified concatenation of lists in getRequestBase().

* In O1::onTokenRequestFinished(), added extra check to if
  "oauth_callback_confirmed" is set to true. This is required
  by RFC 5849 (section 2.1) and is also menioned in the
  twitter API docs here:
https://dev.twitter.com/docs/auth/implementing-sign-twitter

* Removed the use of string constants done in previous commit
  as I feel, I can do ALL such conversions in a separate
  commit which will be easier to review.
Added new header file to contain string and other contants
Added global header file.

o2globals.h file has been added to contain all string and
integer constants used inside O2.

Also added a missing QNetworkRequest::setHeader() to
O1::exchangeToken() to set the HTTP content type field.
Removed copyright header accidentally added by Qt creator
Addressed review comments
Fixed code blocks according to existing style

* Renamed constants in o2globals.h. All contants are now
  prefixed with "O2_".
* Removed explicit "inline" keyword from getHatsh() function.
Merge pull request #5 from mandeepsandhu/master

Minor changes to O2