support overriding default template options from the toml file

[RonnyPfannschmidt]

when working with line statements, the default of block trimming is pretty unfortunate,
it would be a big help to choose custom template options while defaulting to just setting trim_blocks = True

[adiroiban]

I think that we should also have lstrip_blocks = True , and instead of overriding it from the config, this should be the "normal" behaviour see #57