Created a hierarchy of abstract JVM Environments.

The class JVMEnv is now abstract, to be used as base class for all
domains implementing abstract JVM environment. The old implementation
has been renamed as JVMEnvFixedFrame. Analogous changes for domains.
Add some debugging code to BafMethod.
Activate automatic deletion of trailing whitespaces in Eclipse.
Add a new implementation of JVMEnv 

The JVMEnvDynFrame implementation is much more complex than the
FixedFrame implementation, since it expands and contracts the numerical
property according to expansion and contractions of frames. It could be
useful for methods with many parameters or when objects are introduced n
the analyzer.
Add more debugging statements in BafMethod