HTK scripts for en, data-gathering scripts for cs

This version of mkorvas:asr_scripts contains updated scripts for HTK for English, used in last training/testing on the current English data. It also contains several updates to data-gathering scripts, especially for Czech.

An important fix is in the files alex/tools/asr/train_voip_en.sh and alex/tools/asr/ in concert with alex/tools/asr/bin/train_mixup.sh where wrong model numbers were used for evaluation before.

Data-gathering scripts for Czech were not working before this commit, now they work nicely. Changes were made especially in handling Unicode and filtering non-speech events.