Whitespace cleanup: Remove tabs

Whitespace cleanup: Remove tabs

This patch removes all tabs hidden inside the source tree and replaces
them with 4 spaces.

Command used for this:
    find . -type d \( -name bluetooth \) -prune -o
    -regex '\(.*\.[hc]\|.*\.cc\)' -a -not -name 'reserve*.[ch]'
    -a -not -name 'gnt*.h' -a -not -name 'adrian*'
    -exec sed -i -e 's/\t/    /g' {} \;

The excluded files are mirrored files from external sources containing
tabs.