Improve yaml error messages

[jimboca]

Catch yaml errors and try to give good feedback.

Traceback (most recent call last):
  File "./write_profile.py", line 10, in <module>
    config_data = yaml.load(config_file)
  File "/usr/local/lib/python2.7/dist-packages/yaml/__init__.py", line 71, in load
    return loader.get_single_data()
  File "/usr/local/lib/python2.7/dist-packages/yaml/constructor.py", line 37, in get_single_data
    node = self.get_single_node()
  File "/usr/local/lib/python2.7/dist-packages/yaml/composer.py", line 36, in get_single_node
    document = self.compose_document()
  File "/usr/local/lib/python2.7/dist-packages/yaml/composer.py", line 55, in compose_document
    node = self.compose_node(None, None)
  File "/usr/local/lib/python2.7/dist-packages/yaml/composer.py", line 84, in compose_node
    node = self.compose_mapping_node(anchor)
  File "/usr/local/lib/python2.7/dist-packages/yaml/composer.py", line 127, in compose_mapping_node
    while not self.check_event(MappingEndEvent):
  File "/usr/local/lib/python2.7/dist-packages/yaml/parser.py", line 98, in check_event
    self.current_event = self.state()
  File "/usr/local/lib/python2.7/dist-packages/yaml/parser.py", line 428, in parse_block_mapping_key
    if self.check_token(KeyToken):
  File "/usr/local/lib/python2.7/dist-packages/yaml/scanner.py", line 116, in check_token
    self.fetch_more_tokens()
  File "/usr/local/lib/python2.7/dist-packages/yaml/scanner.py", line 220, in fetch_more_tokens
    return self.fetch_value()
  File "/usr/local/lib/python2.7/dist-packages/yaml/scanner.py", line 576, in fetch_value
    self.get_mark())
yaml.scanner.ScannerError: mapping values are not allowed here
  in "config.yaml", line 6, column 7
Makefile:32: recipe for target 'config.yaml' failed
make: *** [config.yaml] Error 1

[jimboca]

The above is likely missing a space after the colon for

name: Some Name