optional location & options arguments

closes #206
Merge pull request #208 from rvagg/optinitargs

optional location & options arguments
update dependencies
@0.18.0
db.batch().put() does not honor original options (like valueEncoding)

I encountered this when using `valueEncoding: "utf8"` on the levelup constructor, and then running `db.batch().put().write()` -- my values were just the Object.toString().  All this does is make the batch API use the same options call that the main levelup path does.
Merge pull request #215 from mcavage/patch-1

db.batch().put() does not honor original options (like valueEncoding)
update changelog
chained batch options fix
readable-stream@1.0.x on all node versions
add basic DNT config
notes & test for readable-stream@1.0.x
@0.18.2 revert to readable-stream@1.0.x
fix logo
fix formatting
doc: minor corrections
Merge pull request #229 from guybrush/doc

doc: minor corrections
doc: fix leveldown method wording
add 'range' keyword to createReadStream docs
refactor encodings and codec out of util

encodings is a separate file to simplify dependency tree,
since util needs to depend on encodings to create default options correctly.
decouple codec from levelup parts, so that it is possible to supply arbitary encoding strategies