feat(preprocessor): Capital letters in binary files extenstions

Use lower case file extension to detect if it is binary

Closes #1508

lib/preprocessor.js

@@ -47,7 +47,7 @@ var createPreprocessor = function (config, basePath, injector) {
 
   return function preprocess (file, done) {
     patterns = Object.keys(config)
-    var thisFileIsBinary = isBinary[path.extname(file.originalPath)]
+    var thisFileIsBinary = isBinary[path.extname(file.originalPath).toLowerCase()]
     var preprocessors = []
 
     var nextPreprocessor = function (error, content) {

test/unit/preprocessor.spec.coffee

@@ -14,6 +14,7 @@ describe 'preprocessor', ->
         'b.js': mocks.fs.file 0, 'content'
         'a.txt': mocks.fs.file 0, 'some-text'
         'photo.png': mocks.fs.file 0, 'binary'
+        'CAM_PHOTO.JPG': mocks.fs.file 0, 'binary'
 
     mocks_ =
       'graceful-fs': mockFs
@@ -195,3 +196,21 @@ describe 'preprocessor', ->
       expect(fakePreprocessor).not.to.have.been.called
       expect(file.content).to.be.an.instanceof Buffer
       done()
+
+
+  it 'should not preprocess binary files with capital letters in extension', (done) ->
+    fakePreprocessor = sinon.spy (content, file, done) ->
+      done null, content
+
+    injector = new di.Injector [{
+      'preprocessor:fake': ['factory', -> fakePreprocessor]
+    }]
+
+    pp = m.createPreprocessor {'**/*': ['fake']}, null, injector
+
+    file = {originalPath: '/some/CAM_PHOTO.JPG', path: 'path'}
+
+    pp file, (err) ->
+      expect(fakePreprocessor).not.to.have.been.called
+      expect(file.content).to.be.an.instanceof Buffer
+      done()