update deformatter (apertium-destxt) escape chars

[singh-lokendra]

fix: #92

Update deformatter to handle all the escape characters https://github.com/apertium/apertium/blob/c1b6b446b25bb22d74fc579ebb48b7140aa09b85/apertium/txt-format.xml#L8

[sushain97]

(i'm fine with us switching to GH actions but it should really be a separate PR, imo)

[singh-lokendra]

I noticed travis builds weren't working so I added the workflow file. I'll make a separate PR for GH acions

[eagad]

@Vaydheesh can you also include ['*', '#', '+', '~'] in escape_chars list, please?

[singh-lokendra]

@eagad The escape_chars is used to wrap apertium-destxt which is generated from txt-format.xml.
Since I am not from linguistics background, I don't know whether this change has potential to break things or not.
Maybe other developers can clarify on implications of this change

[singh-lokendra]

can you also include ['*', '#', '+', '~'] in escape_chars list, please?

@sushain97 any thoughts on this?

[TinoDidriksen]

*#+~ are not escaped in the input - see https://github.com/apertium/lttoolbox/blob/master/lttoolbox/fst_processor.cc#L39

They are escaped when expanding: https://github.com/apertium/lttoolbox/blob/master/lttoolbox/expander.cc#L116

But de/re-formatters must not touch *#+~.