Changed post editing settings

[bmarkus]

Changed editing settings for posts. Now posts can be edited or deleted within 30 minutes only, previously it was any time. It is enough to send new post and correct it but avoids to delete or edit them later and making all others answering look stupid. It happened already few times when a guy removed all his posts and deleted his account also.

Also it is more easier to follow thread without edited old post what you do not expect to be changed.