Initial commit.
Added a new elisp module "javaimport.el", aiming at reinforce the capabilities to import a class form any source file within the current project file tree, any library (JAR) used in the current project, or from standard JDK/GDK APIs.

As a first step, in this commit I added the function to scan all the classes
defined with a given source file.

 #ISSUE: if the word "class" is used in comments, it is wrongly used as a class
declarator and the word after is used as the class name!
=> Suppressing all comments within the temporary buffer before scanning classes
would correct the problem.
Issue resolved in javaimport.el (see last commit). Removing all comments (AND string litterals!) allowing resolving the issue.
javaimport.el: I made the returned class list include the access modifier set on each class.

Before:
(class1 class2 ... classN)

After:
((class1 access-mod1) (class2 access-mod2) ... (classN access-modN))
Corrected bug in 'javaimport-scan-defined-classes-in-source'
Added a function to get all defined classes in Java/Groovy source files contained in given directory.
Fixed bug in 'javaimport-remove-all-comments-in-buffer', Java/Groovy one-line comment begin from '//', not necessarily from the beginning of the line...
Add message output to testing function.
When no access modifier is specified to detected class, the mention "package-private" is used instead of nil.
Corrected a bug in 'javaimport-remove-all-string-litterals-in-buffer': string litterals may contain escaped double-quotes.
Add the elementary function to scan all the classes defined in a JAR file (requires arc-mode).
Finalized class provider looking for all classes in all JARs located in the current folder.

I may need to filter more the classes detected, as for example inner-classes used for Groovy closures may be wrongly detected
as classes that can be imported in source code (something looking like package.MyClass$InnerClass$1_closure$11_closure2).

There is now 2 providers: one looking for classes directly defined in Java or Groovy source files (.java/.groovy files),
and one scanning JAR file contents for all compiled classes inside (.class file).

TODO: make a provider returning classess stored in some kind of cache files, being just text files with a custom list of class
we want to be proposed as candidated when searching for imports (it will be typically used for storing classes from JDK or Groovy SDK,
but it can be used to add any list of classes we want provided by the tool).
Added a provider that scan classes in API HTML documentation like JDK "allclasses-noframe.html" (which is just a bunch of raw links to each class documentation page).