[Application] Parse WGT manifest as if it were a XPK manifest

Since the current code is too tied on an application being packaged in the
XPK format -- and thus assuming things are using a "low level" representation
of its metadata, it is simpler in this stage to just parse the XML file from
WGT widgets and create the same in-memory data that the XPK packages contain.
[Application] If loading from WGT, use provided Tizen App ID from config.xml

The Tizen App ID must be used instead of the Crosswalk auto-generated one as
some features require it.  MessagePort is one example: applications
uses these IDs to create the necessary communication channels.
[Application] Load application after it has been extracted

Required to obtain the application ID from config.xml. Won't make any
difference for XPK-packaged applications.
[Tizen] Consider legacy Tizen IDs as valid IDs

Modify the ID validation function to also accept the 10-character ID that is
used by Tizen for application IDs.  Keep the XPK ID validator as well if the
ID size is different from 10.
[Application] Compare application IDs in a case insensitive way

When loading a resource from an `app://` URL, the application ID is used as
a hostname.  GURL converts that to a lowercase string, which makes it
impossible to use the URL hostname as a key to ApplicationDataMap if
Crosswalk is loading resources from an application that has been packaged in
WGT format.

Modify the ApplicationDataMap typedef to perform case insensitive search.
[Tizen] Consider "app://" protocol while loading web-ui-fw data
[Runtime] If running on Tizen, look for Tizen extensions by default
Merge pull request #1490 from lpereira/wgt-as-xpk

Add support to load WGT packages on Tizen