Switch from deprecated QRegExp to QRegularExpression

Remove the code supporting old Qt versions.

WARNING, this breaks compatibility with Qt 4.3

Implements the UI part of the Marks feature and connect it to the backend.

Fixes #4

Complete implementation of Marks (backend).

Also implemented unit tests for it.

First implementation of the Marks backend.

Also implements some basic unit tests at the LogFilteredData level.

Remove some tests affected by race conditions.

Also add a script to run unit tests.

Refactor the unit tests to avoid race conditions.

Fix the nasty info line flash when the loading/search is short.

We now ignore progress updates of 0% and 100%.

Correct update search on non LF terminated lines.

When an update search is made, glogg now re-search the last line in case
it has changed.

Build tests with optimisation and allow profiling.

Refactor LogDataWorkerThread to put the common code to the base class.

Implement the low level part of 'update' searches.

Refactored LogFilteredDataWorkerThread to handle "updating" searches.

No functionality added in this commit.

Update the getLength/getMaxLength functions to count expanded tabs.

Fix race conditions when interrupting a loading by another loading.

The operations in LogData are now queued and only started when the previous one
has been reported done by the worker thread.

Fix file size and number of lines for very big files.

Now uses qint64 for both file size and line number (but not for match index so
far).

Implements a new FileWatcher in order to watch even a non-existent/deleted file
(via its directory).

Hack around the race condition interruptSearch/clearSearch when entering a blank search.
Minor unit test correction.

Make LogFilteredData block if a second search is requested.
Improves the tests for LogFilteredData.

Implementation of asynchronous searches (LogFilteredDataWorkerThread).