[ck2cti] Improve error messages associated with missing input files

Partial cherry-pick of trunk r2856.

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@2921 02a645c2-efd0-11dd-984d-ab748d24aa7e
[SCons] Workaround SCons dependency bug with Cygwin

Cherry-pick of trunk r2862

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@2922 02a645c2-efd0-11dd-984d-ab748d24aa7e
[Thermo] Check composition strings for invalid float literals

Cherry-pick of trunk r2866

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@2923 02a645c2-efd0-11dd-984d-ab748d24aa7e
[ck2cti] Make 'PCHEB' and 'TCHEB' keywords case insensitive

Fixes Issue 213.

Cherry-pick of trunk r2878.

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@2924 02a645c2-efd0-11dd-984d-ab748d24aa7e
[Doc] Add note about how to fix Sundials CMakeLists.txt

The Sundials CMakeLists.txt was not correctly updated for the 2.5.0 release, and
builds a version of Sundials that still claims to be 2.4.0. This leads to
compilation errors since some Sundials functions have changed signatures between
2.4 and 2.5, and Canteran needs to distinguish between the two.

Cherry-pick of trunk r2887.

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@2925 02a645c2-efd0-11dd-984d-ab748d24aa7e
[Doc] Update version specified in git/svn checkout commands

Cherry-pick of trunk r2920.

git-svn-id: https://cantera.googlecode.com/svn/cantera/branches/2.1@2926 02a645c2-efd0-11dd-984d-ab748d24aa7e