warning: `code' might be used uninitialized in this function

Added BAD argument check to the following IMAP command handlers:

APPEND, STORE, LIST, EXAMINE, STATUS and SEARCH

LIST_imap() had a second level of indentation at 9 characters and not 8.

Corrected some IMAP variable names and whitespace issues.

Added missing $

... when doing upload it would return the wrong values at times. This
commit attempts to cleanup the mess.

Bug: http://curl.haxx.se/mail/lib-2013-08/0109.html
Reported-by: Mike Mio

When removing an already removed handle, avoid that to ruin the
internals and just return OK instead.

'struct monitor', introduced in 6cf8413e, already exists in an IRIX
header file (sys/mon.h) which gets included via various standard headers
by lib/easy.c

cc-1101 cc: ERROR File = ../../curl/lib/easy.c, Line = 458
"monitor" has already been declared in the current scope.

Reported-by: Tor Arntsen

Corrected the call to logmsg() in the IMAP SEARCH handler from commit
4ae7b7ea as it should have been outputting the what argument and
not the test number.

When we introduced curl_easy_perform_ev, this got a slightly modified
call trace. Without this, test 165 causes a false positive valgrind
error.

Without this, test 165 triggers a valgrind error when ran with
curl_easy_perform_ev

When waiting for a 100-continue response from the server, the
Curl_readwrite() will refuse to run if called until the timeout has been
reached.

We timeout code in multi_socket() allows code to run slightly before the
actual timeout time, so for test 154 it could lead to the function being
executed but refused in Curl_readwrite() and then the application would
just sit idling forever.

This was detected with runtests.pl -e on test 154.

warning: implicit declaration of function 'checkpasswd'

Moved the calls to checkpasswd() out of the getparameter() function
which allows for any related arguments to be specified on the command
line before or after --user (and --proxy-user).

For example: --bearer doesn't need to be specified before --user to
prevent curl from asking for an unnecessary password as is the case
with commit e7dcc454.

Added the --bearer option to the help output

Added the ability to specify an XOAUTH2 bearer token [RFC6750] via the
--bearer option.

Example usage:
  curl --url "imaps://imap.gmail.com:993/INBOX/;UID=1" --ssl-reqd
  --bearer ya29.AHES6Z...OMfsHYI --user username@example.com

warning: 'variable' may be used uninitialized in this function

I brought back security.h in commit bb552933. As we actually
already found out back in 2005 in commit 62970da6, the file name
security.h causes problems so I renamed it curl_sec.h instead.