[FindBool] Made editor responsible of exceptions

SearchStrategy findNext and findPrevious no longer throw excetions but rather
return false when the pattern isn't found.

This will allow some refactoring.

This also means that now the Editor is responsible of throwing the exception.
[FindBool] Created findIn private method
Fixed CS
[FindBool] Renamed LineSearchStrategy to SameSearchStrategy
[FindBool] Created LineSearchStrategy

An abstract class which prepares a subset of lines for the look up.
[FindBool] Added before/after to find methods

This allow to look for a pattern before/after a given location.
If no location have been given, the File's current line is used.
[FindBool] Removed has

This can be replaced by findNext($file, $pattern, 0)
[FindBool] Refactored NotSupportedException

Removed the array
[FindBool] Updated the documentation
[FindBool] Removed FactoryMethod

To be debated here: #25
Merge branch 'user/find-bool'