[Help-smalltalk] Some fix in the smalltalk-mode

[Mathieu Suen]

Hi Paolo

I made some small fix in the smalltalk mode.
The syntax-table is simplify and now the class declaration beginning with a 
namespace work: 

i.e:

STInST.RBProgramNode sublclass: Foo [
...
]

For the time being I only recognize one namespace. No nested namespace.

Mathieu