[Proposal 890] Clarifying two-week clause for house meetings

Amending constitution based on results from Simmons house meeting 3/30/2014 (proposal 890):

Unofficial Text:
Clarifying the two-week clause for house meetings by adding that we only consider weeks when MIT classes are in session (e.g. Not during the summer or over breaks)

Official Text:
In section 2.4.1 of the Simmons constitution, replace:

"at meetings that are open and announced to all members of the House and occur at least once within every two-week period."

with

"at meetings that are open and announced to all members of the House and occur at least once within every two-week period during spring and fall semesters that MIT classes are in session."