Architecture Page: Improve Clarity

Intergrate feedback from @tacurran with previous revisions to architecture page, improving clarity, correcting typos, adding links, and improving formatting.

Signed-off-by: Dominic Serio <dominic@flynn.io>
Architecture Page: Improve Clarity

Signed-off-by: Dominic Serio <dominic@flynn.io>
Website: Tweak development page

Basic changes to formatting of Dev page

Signed-off-by: Dominic Serio <dominic@flynn.io>
Merge branch 'arch-doc' of https://github.com/flynn/flynn