Don't recursively remove line endings, when creating plain text e-mail from html one

In In-Portal 5.2.0 release ability to separately enter HTML and Plain-text versions of e-mail was added.
Playing around with this feature I discovered that plain text version of e-mail being severely transformed in terms of line ending before it gets sent to recipient.

Here are the transformations I've found:

1. trailing line endings are replaced with a single line ending
This obviously was designed from HTML version of e-mail since there new line symbols doesn't mean much (unless inside a < pre > tag of course). As a fix I've kept this behavior only for HTML version of e-mail.

2. new lines, produced due m_DefineElement tag execution are removed
This is a bug, but since we only looked at HTML e-mail version where this wasn't noticeable we didn't knew this was happening at all.

To test the fixes I've made I've added "Send" button (visible only in debug mode) to e-mail events list. It just sends an e-mail event. I'm sure that nobody won't be against having this button also commited.
Beware, that not any e-mail event can be sent this way. For example e-mail events that rely on data to be preloaded by code which calls them would just be sent empty.