change screenshot, remove extra \n, fix repeated MB
add FreeBSD compatible mongoose version
add simple http cache headers
implement if-modified based http cache system

- add missing headers like "Vary" and content enconding
- added "no-cache" to stats.json
add process argument list to stats.json
remove vendors submodules
Squashed 'vendor/sigar/' content from commit 1898438

git-subtree-dir: vendor/sigar
git-subtree-split: 189843858ecd8da7fb94a6b274269877c2416b3a
Merge commit '5d63450ca1aebe4cee99d317f17c8683639f2ade' as 'vendor/sigar'
Squashed 'vendor/json-c/' content from commit db117ca

git-subtree-dir: vendor/json-c
git-subtree-split: db117ca02bdd744a54f7258a2927aa97edbc5f0d
Merge commit '6492130d90975df98245ab40daa641b9d401a2dd' as 'vendor/json-c'
Squashed 'vendor/mongoose/' content from commit 725c304

git-subtree-dir: vendor/mongoose
git-subtree-split: 725c30446cae712310bbb9b00b302135e5109485
Merge commit 'aaf1bb7e0293e4b75a9acac02c50793b0fd581f0' as 'vendor/mongoose'