Spelling fixes in comments and descriptions, patch by luzpaz.

check_blender_release/check_static_binaries.py

check_source/check_style_c.py

utils/blend2json.py

utils/blender_theme_as_c.py

utils/cycles_timeit.py

utils/git_log_review_commits.py

utils/git_log_review_commits_advanced.py

utils/header_clean.py

utils/rna_manual_reference_updater.py

utils_build/cmake-flags

utils_ide/qtcreator/externaltools/qtc_cpp_to_c_comments.py

utils_ide/qtcreator/readme.rst