Rakefile: fix spacing

Rakefile

@@ -116,16 +116,16 @@ end
 
 # get dependencies of a file
 # done is a list of already known dependencies
-def dependencies(source, done=[])
+def dependencies(source, done = [])
   d_path = source.ext("d") # get the dependency file
   Rake::Task[d_path].invoke # ensure the dependency file exists
   d_file = IO.read(d_path) # read the dependencies from dependency file
-  d_file = d_file.split(': ')[1].gsub("\n",'').gsub('\\ ','').gsub(/\s+/,' ').split(' ') # get a list of dependencies
+  d_file = d_file.split(': ')[1].gsub("\n", '').gsub('\\ ', '').gsub(/\s+/, ' ').split(' ') # get a list of dependencies
   d_list = [] # list of dependencies
   # only save dependencies which are in our source directories
   d_file.each do |d|
     SRC_DIRS.each do |dir|
-      if File.dirname(d)==dir then
+      if File.dirname(d) == dir then
         d_list << d
       end
     end