Library consistency check

Adds a new function to HybridMobileEngine to check if the underlying
library is compatible with the ProjectGenerator. It goes through every
HybridMobileTemplateResolver supported by the engine and checks if all
the referenced files exists on the library. This is not a full proof
check but it should elliminate most obvious cases of a new engine not
working with the tools.
Refactor ProjectGenerator extension point

ProjectGenerator extension point needs to assume more responsibilities
with the introduction of engine support. It has been renamed to
PlatformSupport and now provides several delegates for supporting a
platform.
Support for precompilation

Now that we are using standard distros of Cordova we need to precompile
the framework libraries. This adds methods to HybridMobileEngine for
precompilation. Also adds precompilation to selection dialogs so that
the consistency checks are done properly.
Precompilation and consistency check before project generation

Does a precompilation and a library consistency check during project
generation
Validate the page if active engine does not present

When an active engine for a project can not be determined property page
does not validate and the initial state of the page is wrong. Adds a
validation if an active engine is not selected. Also exposes the page id
as a constant.
Rename extension point attribute

Renames the delegate attibute to projectGenerator to sync with the
schema changes.
Error handling for engine problems

Introduces a status handler for problems that may occur during project
generation due to problems with active engine. Also starts a framework
for generally handling the errors. Export wizards now use this new
framework to resolve engine related issues the same way as they occur
during launch.