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.

Add new methods to AbstractLogData to expand tabs.

Works but slow, need optimisation.

Ensure selections stay within limits of the file.

Move the sending of the first load notification (0%) to the worker
thread to avoid a race condition on Linux.
Also change the default log level to DEBUG instead of DEBUG4.

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.

Add a stop button in the loading progress bar.

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).

Tests if the file exists before opening it.
This is because LogData now happily accepts a non existent file.
The unit test is also fixed accordingly.

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

Add a "random page" performance test.

Add notification and clear the search when the file is truncated.

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

Make LogData (at least mostly) thread-safe.
Also fix a bug in the line numbering (it started at line 1) and re-add the full sequential read test.

Adapted CrawlerWidget to work with async searches.

Make LogData blocking when a loading is in progress just like LogFilteredData.
Added a script to keep track of line/branch coverage.

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

Implementation of asynchronous searches (LogFilteredDataWorkerThread).

Implement asynchronous loading and indexing in a worker thread. Also add a more comprehensive unit test suite for LogData.

Rename to glogg!

Add a simple QListString implementation of logData.

Correct an off limit index in the random page unit test.

Update unit tests for lodata (added page by page perf test).

Created the LogFilteredData class and associated unit test.