The tone is now faded in and faded out (10ms linear fade window on each
end).  The removes the "clicking" noise that could be heard in previous
version when the tone started and began.
I added a user-input edittext so the user can set the frequency
generated from the linear sample button
Merge remote-tracking branch 'ednovak/master'
	modified:   src/net/ednovak/covert_talk/main.java
1. Change genTone() --> genToneFaded()
2. Restore the original genTone()
3. Add a new method customHail() to generate frame with hail sequency.
   Also use raised cosine filter here, so no longer need the genToneFaded() any more.