Merge pull request #417 from dbetebenner/master

Update to 1.1-9.0
SIMEX: Make content area (progression) match grade progression
Merge branch 'master' of github.com:SchoolView/SGP
Don't use gc() - getting segfault - 'memory not mapped' issues after running SIMEX...
Revert "Don't use gc() - getting segfault - 'memory not mapped' issues after running SIMEX..."

This reverts commit 07c39905d711e6b2cb0296c555da89f5b8bb91e8.
use of copy(…) can cause memory segfault
Add key to slot.data
Revert "Add key to slot.data"

This reverts commit a59618a80585d9b78f93c6b3f30caad449f0141d.
SEGFAULT ISSUE:  Get rid of assign by reference and do a join/merge instead
Revert "use of copy(…) can cause memory segfault"

This reverts commit 365a76f93f32fd952b2b8aec663e2e43e10e5da9.
Merge pull request #418 from dbetebenner/master

Update of combineSGP to better faciliate merging of baseline SGPs
Merge pull request #419 from dbetebenner/master

Update of combineSGP
Merge branch 'master' of github.com:SchoolView/SGP
Revert "SEGFAULT ISSUE:  Get rid of assign by reference and do a join/merge instead"

This reverts commit 6d063d3f1f675fc2cc125d1060effa9425a4cdb7.
Add check before keying (only needed when there is "mult membership" present)
Merge pull request #420 from adamvi/master

Change setkey in summarizeSGP and some SIMEX edits
Update of summarizeSGP