[maven-release-plugin] prepare release spoon-core-2.4
[maven-release-plugin] prepare for next development iteration
fix the fragment mode
add test for initEnvironment
fix #38 Fix test case of the initEnvironment method

Remove useless attribute of test class and change default
value for properties file and output directory.
Adds test case for switch statement on a string
Adds test case for try catch whom rethrow exceptions
Adds test cases to test try catch with resources.
Improves model to discern try normal and try with resource.

Creates CtTryWithResource/Impl to represent a try-with-resource
and adds posibility to visit it. Improves tests to use the new
interface CtTryWithResource when it used the old one, CtTry.
adds ROADMAP.md
add a missing visit method in CtAbstractVisitor
Merge pull request #102 from petitpre/VisitorUpdate
Removes all methods deprecated after the release 2.4.
Improves model to add multi types for local variable.

Creates MultiTypedElement interface and extended by
CtLocalVariable to add the possibility to have multi
types for a local variable. For example, it is used
in multi catch in Java 7: there is one variable and
several types.
Merge pull request #95 from GerardPaligot/QA_38
Merge pull request #103 from GerardPaligot/clean-release-2.4
Merge pull request #101 from monperrus/roadmap
adds a first version of the contribution rules
Merge pull request #105 from monperrus/contributing
clarifies the responsibilities of Template and TemplateParameter