Documentation of command line parameters + other small changes

Change-Id: I355014afbe2c2a954e559125bd1ec4da56e7f16c
Make sure revisions of a page are sorted by their id

Change-Id: Id5a79bf9b4ee7a7d3fed9c340db34f4673207b0c
Performed some of Platonides' suggestions

+ fixed a bug with creating new dumps

Change-Id: I05c2c5202b97848bbc5a7a8374713fe9280d4497
Fix and refactoring of previous commit

Change-Id: I620885fa4032d3711ec1b8e9fd281c704c659062
Changed handling of undeleted pages in diff dumps

Change-Id: I63ce069375cdfa71a19021ed06bdd846683b2fdb
Fixed memory issues

- clearing index cache periodically, so that it doesn't grow too much
- fixed memory leaks
- less copying

Change-Id: I1483a2f4855a7faa751dd8ed7ee050b17a0c7204
Write page after its revisions

This is necessary when creating big dumps from XML.
Without this, all revisions of a page have to be kept in memory,
including their texts.
A downside is that this will increase seeking when reading.

Change-Id: Ib6ea9fe67671df7a5686f6a4e441ab95ff6dba01
Don't save namespace as part of title

Change-Id: I794c19db9e36d11d6d05e3bbd7f6f3fe26fb8b0a
Fix comments early, so that check for no changes works right

+ handle another case of overlong comment

Change-Id: Id6424a9e44ba1351396bb7ba994899c088742cb3
Starting text groups for better compression

Change-Id: I42575d934d6b1edb77b355d10e9047fe54961c59
Removed check for trailing zero in decompressed string

With compressed groups, missing trailing zero is problematic.
On the other hand, added trailing zero is now okay.

Change-Id: Ia368b7ef2a198ee327029704e0a19f5b4ae7f84f
Finished text groups

Change-Id: I946da5db3defe175fa2ef0fcf97e17ae8880f41b