add access to instance variables from within object, collection, and result blocks + specs
Merge remote-tracking branch 'upstream/master' into nested-ivars-fix
rearrange PROTECTED_IVARS
set initial ivars on top-level Node
remove conditional that could sometimes instance_eval on current_object when passing a block with no args to #attribute
reorganize and refactor Node#attribute specs

* All Node#attribute specs are now in one place.
* No more usage of `node_wrap` or `wrap` helper methods. Everything is now
  inlined for better readability
refactor bldr method to take advantage of Node parent option to set ivars
yard docs for :parent option
cleanup and comments
Merge branch 'nested-ivars-fix' into nested-ivars

Conflicts:
	lib/sinatra/bldr.rb
Node#attribute can safely be passed a block with no arity

This commit also adds a spec ensuring that the context is
a Bldr::Node instance. This behavior is a breaking change
from how bldr currently operates.

The behavior itself was introduced in d0bfbd8, but this commit
adds a spec for it.
add specs to ensure ivar access in attribute blocks
nest tilt template specs under Bldr module
ensure included partial have access to ivars
drop 1.8 support
update pending 0.7.0 release notes
history typo
add ability to treat collections like enumerations w a block var
spec to ensure collection blocks have access to ivars
add spec for object block variables