lowered case in email search + variable re-use in updateContact()

Constant Contact email search is case-sensitive and recommends
searching by the lowercase version of the address, so I added
some calls to strtolower() in the searchContactsByEmail. I also
updated the updateContact() function to use a variable that was
defined in a previous line.
Merge pull request #10 from purdy/master

Merged strtolower() function in email searches and a small fix to include a defined variable that we ignored.