rework function/method signatures in main.py and parallelbuild.py to follow build_options/build_specs scheme used for EasyBlock/EasyConfig
fix minor remarks
move cleanup_logfile to an inner function, clean up end cleanup
fix use of 'magic' string for output_dir argument to build_easyconfigs_in_parallel function
move cleanup_logfile function to filetools module, stop returning path to removed log file in main function
move find_easyconfigs function to filetools module
import missing print_msg required by cleanup
move retrieve_blocks_in_spec from easyconfig.format.one to easyconfig.tools, move process_easyconfig from main to easyconfig.tools
move skip_available to easyconfig.tools and optimize it a bit
move resolve_dependencies, robot_find_easyconfig and find_resolved_modules functions to easyconfig.tools module
move process_software_build_specs function from main to tools.options module
move obtain_path from main to easyconfig.tools module
move get_build_stats function to tools.build_log (avoid importing tools.systemtools there)
move dep_graph function from main to easyconfig.tools (including required imports)
move search_file function from main to filetools module and introduce build_options in function signature
move build_and_install_software from main to easyblock module
fix typo
add missing import
add missing import for filetools module in easyblock module
fix missing import