Simplify code_prep.split_line, fix it's unit test.

I presumed that the failing unit test was wrong and the previous implementation was working as it should.

gooey/code_prep.py

@@ -38,11 +38,8 @@ def split_line(line):
   # splits an assignment statement into varname and command strings
   # in: "parser = ArgumentParser(description='Example Argparse Program')"
   # out: "parser", "ArgumentParser(description='Example Argparse Program"
-  # take/dropwhile used to avoid splitting on multiple '=' signs
-  not_equal_sign = lambda x: x != '='
-  varname = ''.join(takewhile(not_equal_sign, line)).strip()
-  command = ''.join(dropwhile(not_equal_sign, line))[2:]
-  return varname, command
+  pieces = line.split('=', 1)
+  return pieces[0].strip(), ''.join(pieces[1:]).lstrip()
 
 def update_parser_varname(new_varname, code):
   # lines = source.split('\n')[1:]

gooey/code_prep_unittest.py

@@ -8,7 +8,7 @@ class TestCodePrep(unittest.TestCase):
   def test_split_line(self):
     line = "parser = ArgumentParser(description='Example Argparse Program')"
     self.assertEqual("parser", code_prep.split_line(line)[0])
-    self.assertEqual("= ArgumentParser(description='Example Argparse Program')", code_prep.split_line(line)[1])
+    self.assertEqual("ArgumentParser(description='Example Argparse Program')", code_prep.split_line(line)[1])
 
   def test_update_parser_varname_assigns_new_name_to_parser_var(self):
     line = ["parser = ArgumentParser(description='Example Argparse Program')"]
@@ -54,4 +54,4 @@ parser.parse_args()
 
 if __name__ == "__main__":
   #import sys;sys.argv = ['', 'Test.testName']
-  unittest.main()
+  unittest.main()