Recent projects loading bug

- Problem :

When trying to load a previously loaded project with the File/Projects/ subcommands, an error will occur if the selected project file tries to access the file system with relative path names.

e.g. : In a given main.tcl project file, we have the command "source ./myProcs.tcl"

=> this command works if the project is opened normally
=> this command fails if the project is opened with the File/Projects/... recent projects command.

- Solution :

In file lib/file.tcl :

Added "catch {cd [file dirname $file]}" at the right place.

Note : My soon to be submitted patch will hold this fix.