Add some cross-references
Merge remote-tracking branch 'saivann/dev' into terms

Conflicts:
	en/developer-guide.md
Shorten a few titles
Merge pull request #48 from saivann/shortentitles

Shorten a few titles
Merge branch 'dev' of https://github.com/saivann/bitcoin.org into opmodes
Merge branch 'opmodes' of https://github.com/instagibbs/bitcoin.org into opmodes
Added cross-references links to Transaction and Contracts sections
Improvements suggested by @saivann
Merge pull request #50 from harding/terms

Add cross-references
Apply a few suggested style improvements
revamped opmode section
Merge branch 'dev' of https://github.com/saivann/bitcoin.org into opmodes
update