Issue warning on joins with character columns and different encodings (bug #5266, #5159)

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/datatable@1096 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Forgot to uncomment the part issuing the warning… (related to last commit).

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/datatable@1097 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Fix for #5117 - rbindlist segfault on all empty data.tables

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/datatable@1098 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Bug fixes + removal of compiler warnings

> Fixed compiler warnings in 'rbindlist' from eddi's commit in 1012.
> Fixed a potential segfault from the last commit (1098) for the case rbindlist(list())
> Fixed #5300 - rbind(DT, NULL) doesn't result in error anymore (no NEWS added as it got changed during 1012 - not a new feature)
> Modified test 680 to reflect eddi's changes in commit 1012 (added sufficient notes).

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/datatable@1099 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Fix for bug #5305 - segfault while grouping on "very large" data + Updated NEWS.

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/datatable@1100 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Minor edit to NEWS entry

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/datatable@1101 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
iradix changed from LSD to MSD

git-svn-id: svn+ssh://svn.r-forge.r-project.org/svnroot/datatable@1102 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Merge branch 'refs/heads/r-forge-git-svn-local'