Update character counter with correct lengths

[jewel-andraia]

http://www.reddit.com/r/RESissues/comments/206gfk/bug_incorrect_character_counter_limit_above_text/cg08xq3?context=3
#157

[jewel-andraia]

note different limit on text posts for subreddits which are text-only.

please add pointers to reddit's definitions in RES code for reference
edit for clarity: i.e.

commentPreview.js

MAX_LENGTHS: {
    WIKI: 50000,  // defined @ http://github.com/reddit/reddit/files/SOMECOMMIT/r2/lib/models/posts.py#L123 

[kevinji]

Also #465

[matheod]

https://github.com/reddit/reddit/blob/3bfe0a2513495f8e667f60ca3efce03f97990e51/r2/r2/lib/validator/validator.py#L574 + https://github.com/reddit/reddit/blob/3bfe0a2513495f8e667f60ca3efce03f97990e51/r2/r2/lib/validator/validator.py#L604-L607

I.e. :

• 10 000 (=L) for simple comments
• 15 000 (=L*1.5) for post in subreddit allowing link post
• 40 000 (=L*4) for post in subreddit self post only