Improve IMAP and SSL/TLS Support, Add Email Headers, Add Runtime Paramters

[BowTyTroll]

Changes detailed in commit comments (copy-pasted below, for quick reference). Tested thoroughly and in production use since July 16th, 2018, without issue.

Main changes are:

• Swapping the unmaintained Net::SMTP::TLS for Net::SMTP
• Adding RFC 2822 compliant email headers, to make spam filters less upset by these emails

# 2018-07-11 v1.4.4     BowTyTroll, TheTroll@BowTyTroll.com
# - Fix SMTP auth when "-usesmtptls"/Deprecated Net::SMTP::TLS for Net::SMTP
# - Add "-smtpehlo" option, with default value hostfqdn(), for SMTP HELO/EHLO
# - Add RFC 2822 compliant From, Date and Message-ID headers to emails
# - Add default imap port variables
# - Correct IMAP SSL/TLS port default from 585 to 993
# - Correct missing require for IO::Socket::SSL if using explicit IMAP SSL
# - Make "INBOX" the default $imapfolder
#
# 2018-07-11 v1.4.5     BowTyTroll, TheTroll@BowTyTroll.com
# - Add missing require directive for Mail::IMAPClient, when '-useimap' given
#
# 2018-07-14 v1.4.6     BowTyTroll, TheTroll@BowTyTroll.com
# - Add statfile directory parameter ('statfiledir')
# - Make default statfile directory the script directory (NOT working directory)

[bentolor]

Thank you very much @BowTyTroll for your major contribution for check_email_loop.

I really liked the clean commits which made reviewing very easy. I just pushed you changes to master and created according Git tags as well as GitHub release notes.

Hope this helps others, too.

Again: Thank you very much for contributing !