first part of fix for yearend: need to populate glmperiod records as well, for assets and other accounts that carry forward their balances into the next year.
add Unit Test for year end, now checking the glm period records as well for balances on bank accounts (assets)
rollback the transaction if there was a problem with importing the gl batch data.
also: show all problems with the gl batch, not only the first problem.
merge from trunk
merge from lp:~tpokorra/openpetraorg/20140318_year_end