Generating build tree from the command line

Seems like my project.ecc was broken by my attempts to generate the build tree. It works now. I create the project_build directory manually and cd to it before calling nios2ecosconfig, then I pass the project_install path in the --prefix option to nios2ecosconfig. ecosconfig will then create the build directories and the makefile in the current directory which is project_build, and it will create a directory project_install with the include and lib files. The only difference I found in the makefile was that the one generated by nios2ecosconfig uses /ecos-x/ and not /cygdrive/x/.