### Core Libraries

#### ROOT Error Handlers

There is a new rootrc variable which allows to control the installation of the ROOT error handlers. By default the handlers are activated:

       Root.ErrorHandlers:      1

but setting the value to 0 result in no error handlers being installed and the originals remaining in place. This can be useful if ROOT is used in conjunction with other frameworks that already installed their own handlers.

#### TString

TString::Hash() and thus also TMath::Hash() now use `MurmurHash3_x64_128` from http://code.google.com/p/smhasher/ which is public domain. To accelerate the hash in the case of pointers even further, pointers (and same-sized texts) are hashed using a simple bitwise xor. This dramatically increases the hash performance for long texts, and still by a factor 5 for pointers. The pointer case is most visible for certain I/O operations (TExMap).

#### TColor

Add the method `SetAlpha()` to set the alpha value (transparency level) for an existing color.

#### TStyle

The default font set by `gStyle->SetLegendFont()` was ignored.

#### TUnixSystem

- Simplify `Setenv` coding.
- Implement `Unsetenv` using the system function `unsetenv`.

#### TROOT

Implemented new gROOT->GetTutorialsDir() static method to return the actual location of the tutorials directory. This is $ROOTSYS/tutorials when not configuring with --prefix or -Dgnuinstall for CMake.