Added ANSI functionality

[abdullah-if]

Added ANSI functionality, present for long time in Windows version. Obsolete and non-standard yet may cover corner cases. Converter from was found here.

[abdullah-if]

Using ANSI for Bangla writing is non-standard and should not be supported. It is the users who should change rather than Avro. I take back my PR.

[sarim]

Thank you very much for your contribution. I appreciate you contributing to the repo :) Unfortunately this PR isn't suitable for the project right now. Current (javascript) version is in feature freeze. New features would be in v2 (golang version). Also this PR includes a library that is clearly a converter for bijoy, which is a proprietary layout. For obvious reasons I can't accept that code into ibus-avro.

[archisman-panigrahi]

which is a proprietary layout

@sarim Is it that even the layout is copyrighted and cannot be included in any other software?

[oritromax]

@apandada1 Yes :)

[abdullah-if]

Quick question, how Avro in Windows implement ANSI ?