Testing "push" privileges
Fixed some bugs (see below), and confirmed that slope and abundance are estimable

Previous bugs:
1.  Estimation and data-generating models had different treatment of
juvenile survival, and different transformation of adult survival
2.  Issues with having too many rep(XXX, nSites) commands, so that
several times there'd be vectors of length nSites^2

Other changes:
A.  Added parameter labels where possible
B.  Added function to only optimize 1-2 parameters (slope + abundance)