Theme settings and moved .offlineimap directory

Added themes sub-directory to hold .muttrc files that describe color themes
MOdified muttrc to set a theme

Untracked .offlineimap directory as it shouldn't be under version control.
Whoops.
Cleaned up .offlineimaprc.

Cleaned up alignment of attributes in .offlineimaprc file.
Setup second account.

Added an IMAP account to the mix.

Added accounts sub-directory to .mutt directory to hold a file for each
account. These are sourced from within the primary .muttrc file.

Removed account specific information from muttrc.

Added second account to offlinemaprc so that mail can be retrieved.

Added second account to msmtprc so that mail can be sent.
Merge pull request #3 from zanshin/imap

Added IMAP account as second account.