Improve/Simplify brightness (F6) popup window logic.
Correct for some invalid ENC encoding, and log all S57 Warnings and errors.
Improve Options->Plugins panel to reflect PlugIn enabled state correctly
Correct for faults from invalid characters in some navobj fields.
Correct for possible fault on canvas emboss image
Improve S52 PLIB standard compliance.
Correct for multiple AIS alert sound instances FS#1030
Correct AIS alert sound test logic on Windows
Stop email sending when Login and/or Code not entered
Merge pull request #75 from Ptizef/master

Stop sending emails to Zygrib when Login and/or Code not entered
Merge branch 'master' of https://github.com/OpenCPN/OpenCPN into devga
Signed-off-by: gilles working 1