fix(lmweight): changes the upper bound to sensible.

Upper bounds(get_maxpart) retured by the lmweight were vague one, with very high value.
Changed the upper bounds to a more apt bound based on smoothing.
Detailed description of  bounds blogged by olly at: http://survex.com/~olly/lm.html
Merge pull request #5 from samuelharden/lmweight

fix(lmweight): changes the upper bound to sensible.