wip
wip
fix inheritance and encapsulation bugs
merge dev into dev-lorel
implements JavaStackTrace & JavaStackTraceElement
fix tests
Splitting filtering logic from XML processing

Moved the filtering logic, currently restricting the processing to Java questions
with accepted answers and containing stack traces, from the XML reading
to its own class.

This gives the developper an easiest way to tweak or replace the current
filtering logic by extending the XMLEventFilter interface.
Fixed broken line number parsing

Surrounded frame line number parsing in try catch to avoid crashes
whenever the stack trace parser fails to properly detect the frame's
line number (either by leaving leading, trailing or in-the-middle spaces
or leaving some text at the end).

If the line number cannot be read, the default value is -1.
Added stack trace persistence in SQLProcessor

The SQLProcessor now stores the stack trace splitting it into a stack,
links and frames.

All the stack traces added to the database are linked, in the order
given by the parser, to the post they come from.
Merge remote-tracking branch 'origin/dev-lorel' into dev

Conflicts:
	src/main/java/fr/lille1/idl/stackoverflow/Main.java
	src/main/java/fr/lille1/idl/stackoverflow/processors/SQLProcessor.java
Fixing table imports
Fixing test bugs

Fixing bugs in the tests.
Normalizing frames and frames linking

Normalizing frames and frames linking in order to lower space
consumption.
test getExpected(link)
FIX: XML writer document ending

Fixed a bug where the XML writer would end the document with an opening
<posts> tag in place of a closing </posts> tag.
Added stacktrace retrieval method

Added stack trace retrieval method to find posts that contain an exactly
identical stack trace than the one given as input.
Fix: Fixed filtering null pointer issue

Fixed a bug that would make the program crash whenever it tried to read
a non existing attribute in the xml node.

The filter now tries to check if the value it retrieved is not null
before going any further.
fix bug getExistingLink(link)
refactor Link with javalike names
Added little search program for search POC

Added a little search program for search proof of concept and updated
README to explain how the program can be be compiled and used.