Speeding up triggerOnset with deque

- will bring a big speed up, when the trigger list is very longish
- proposed by
  http://pyvideo.org/video/1780/transforming-code-into-beautiful-idiomatic-pytho
Being more pythonic, refactoring

- using else statements in for loops
- proposed by
  http://pyvideo.org/video/1780/transforming-code-into-beautiful-idiomatic-pytho
new options in waveform:
linestyle
grid_color
grid_linewidth
grid_linestyle

remove the linewidth in the _plotEvent

documentation in stream updated
":param data_unit:" documentation corrected
pep8 style correction in  waveform.py
Revert "pep8 style correction in  waveform.py"

This reverts commit 35a523917eb9019309c28396818c4b904042c947.
pep8 style correction in waveform.py
add option "prefix" (default "obspy-") for NamedTemporaryFile
Merge pull request #546 from megies/tempfile_prefix

"obspy-" prefix for temp files
Option to ignore file size check in reading sac files

Checking for consistency between actual and theoretical
file size (from `npts`) can be disabled both in
`SacIO.ReadSacFile()` and in `sac.core.readSAC()`.
This is obtained by passing the parameter: `fsize=False`.

`sac.core.isSAC()` has been rewritten, in order not to
rely on `npts` to check file format, but rather checking
`nvhdr` and `delta`, as in `SacIO.IsSACfile()`.
fixes #550
Testing fsize option in reading sac files

Adds test cases for core.read() and SacIO.ReadSacFile()

See also #549
obspy-scan: plotting rectangles for gaps (instead of lines at start of gap) and new option --print-gaps
minor change to previous commit
fixes #553
fixing a bug introduced in 4e70c059e8f76d3e71da45d31ac31b6759f7b4b2

(IndexError in case of a gapless seed id)
fixes #554
Merge pull request #555 from obspy/554

fixes #554
removing a outdated comment
Making isSAC() more robust
signal: extend coincidence trigger

 - now has possibility to use event template waveforms
 - event triggers that excceed similarity levels get included in results
   even when network coincidence sum is not met
 - tutorial example
 - test, simple doctest for helper routine in cross_correlation
 - changelog