Optimize regex to find parent of mail

[ci2014]

Made the Regex case insensitive and changed the regex to show only the lowercase (which will save some space). Added the aw and wg for german answer and forwarding.

I will add more languages based on this list https://en.wikipedia.org/wiki/List_of_email_subject_abbreviations after more research.

EDIT: Any concerns about adding a field like that one "E-Mail prefixes" in the Language doctype and using those in the regex?

[ci2014]

@rmehta Thanks for merging! Any feedback to this:

Any concerns about adding a field like that one "E-Mail prefixes" in the Language doctype and using those in the regex? This will give the users the ability to define them themselves.

[joolsr]

Can you explain what this will do exactly ?

[ci2014]

Sure. At the moment (after the patch) only english and german prefixes for forwarded mails and replies to mails are considered by the regex.

As there are users, which use other languages than german and english, we need to provide a way for the end user to define the email prefixes for his own language (or of the email program he uses).

The regex is for matching replies and forwarded mails by their subject and append them to the right document.

[joolsr]

@ci2014 Ok. Actually, although I speak English as we communicate with customers who respond in English but speak another language, their replies usually have the re or AW in their own language too.

[ci2014]

@joolsr Yes, that's what I mean. If we don't match by any possible language, it will create a new ticket instead of appending.