Update insallation"

docs/installation.rst

@@ -35,7 +35,7 @@ Or, if you installed via GitHub clone:
 
     pip install -r optional-dependencies.txt
 
-Note, however, that some of these Python dependencies have their own (possibly platform-dependent) requirements. Most notably, python-magic requires libmagic (see `here <https://github.com/ahupp/python-magic#dependencies>`_ for installation instructions), and without this, you'll be relegated to loading all your stims explicitly rather than passing in filenames (i.e., :py:`stim = VideoStim('my_video.mp4'`) will work fine, but passing 'my_video.mp4' directly to an |Extractor| will not). Additionally, the Python OpenCV bindings require `OpenCV3 <http://opencv.org/>`_ (which can be a bit more challenging to install)--but relatively few of the feature extractors in pliers currently depend on OpenCV, so you may not need to bother with this. Similarly, the |TesseractConverter| requires the tesseract OCR library, but no other |Transformer| does, so unless you're planning to capture text from images, you're probably safe.
+Note, however, that some of these Python dependencies have their own (possibly platform-dependent) requirements. Most notably, python-magic requires libmagic (see `python-magic <https://github.com/ahupp/python-magic#dependencies>`_ for installation instructions), and without this, you'll be relegated to loading all your stims explicitly rather than passing in filenames (i.e., :py:`stim = VideoStim('my_video.mp4'`) will work fine, but passing 'my_video.mp4' directly to an |Extractor| will not). Additionally, the Python OpenCV bindings require `OpenCV3 <http://opencv.org/>`_ (which can be a bit more challenging to install)--but relatively few of the feature extractors in pliers currently depend on OpenCV, so you may not need to bother with this. Similarly, the |TesseractConverter| requires the tesseract OCR library, but no other |Transformer| does, so unless you're planning to capture text from images, you're probably safe.
 
 Docker
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