run: don't treat unique_word as a regexp
run: don't treat unique_word as a regexp

Matching each unique_word is executed multiple times for each line in
the file.  The unique_word should be unique for a given trace, so
there is no point in doing a regexp match to begin with.  By doing
this, I get more than 3x performance improvement in my laptop for a
27Mb trace file:

Before:

In [1]: %timeit cr2.Run("/home/javi/src/thermal/results/2014-11-20/odroid-power_allocator-47f694f451b4-2/transporter_5_1/")
1 loops, best of 3: 15.1 s per loop

After:

In [1]: %timeit cr2.Run("/home/javi/src/thermal/results/2014-11-20/odroid-power_allocator-47f694f451b4-2/transporter_5_1/")
1 loops, best of 3: 4.66 s per loop

Change-Id: I3f67345ffee62940eab43dc48408e11a9a039078

derkling/trappy,ARM-software/trappy,joelagnel/trappy,joelagnel/trappy,ARM-software/trappy,derkling/trappy,sinkap/trappy,JaviMerino/trappy,sinkap/trappy,ARM-software/trappy,derkling/trappy,JaviMerino/trappy,sinkap/trappy,joelagnel/trappy,bjackman/trappy,bjackman/trappy,bjackman/trappy,joelagnel/trappy,JaviMerino/trappy,ARM-software/trappy,bjackman/trappy,sinkap/trappy