Americanize spellings
further typo correction

@jburel helped me to find these issues
    yet more typo correction

    @jburel helped me to find these issues
further typos/spellings

mostly suggested by @jburel and @hflynn
extra "although" for @hflynn
fix "customise"
Merge pull request #390 from mtbc/americanize-spellings

Americanize spellings and fix typos