see #548, different way to handle multiple sampint

this should just show an alternative possibility to handle multiple
sampling rates for obspy-scan.
Using proper malloc() while writing MSEED data.

The datasamples pointer in writeMSEED() is now filled with a proper
malloc call and not the old and hackish resizing approach. Now also runs
on Python 2.7.4. Fixes #551.

Also changed the MSTraceGroup to a simple MSTrace as it is only used one
trace at a time.

Requires recompilation of the shared obspy.mseed library.
Fixing confusion of numpy.string_ dtypes.

test_writeAndReadDifferentEncodings() now works across different NumPy
versions. Fixes #552.

Conflicts:
	obspy/mseed/tests/test_mseed_reading_and_writing.py
Bugfix for waveform plotting.

There a slight error in the data binning. It always occurred but only
manifested for certain data lenghts. Also added a test for it.
stream.plot(): More fixes

Found another sample count that messes with the binning. This should
solve the issue.
fixing a failing import
all public C methods need to be listed in .def file for win
arclink: check times in getInventory on channel level instead of
location level (i.e. on downmost level). this can help with faulty
location specifications around OK channel specifications. (see #586)
fixing incorrect entry point for obspy.db features
fixes #489

Conflicts:
	obspy/core/util/xmlwrapper.py
fixing download_url for dev version via easy_install
Small bugfix for blockette 60 initialization.
fixes #554
Replacing the numpy views with true type casts.

Views do not change the underlying data and thus do not work with
custom C code that expects raw data of the correct type.

Conflicts:
	obspy/core/tests/test_stream.py
adding missing import
adding a missing import
remove darwin_compiler_fixup (missing in newer python 2.7
reverting commit 0ef60b8 as xml_doc gets closed too

Conflicts:
	obspy/core/util/xmlwrapper.py
Making setup.py work with OSX compilers.

The clang compiler shipping with newer OSX versions does not honor the
LIBRARY_PATH variable and thus cannot find the gfortran libraries. This
adds a workaround. Works with OSX 10.7 and the latest official XCode
clang version. Also tested with a local gcc installation. Works with
Python 2.6.8 and 2.7.5. Tested with NumPy 1.6.2 and 1.7.1 for each. All
other dependencies where the latest versions from pypi.
fdsn: setting up new submodule basic structure