Workaround for missing `prefix` in UnaryExpression generated by Esprima

See #193
v2.3
Take two.  v2.3.0
Add README syntax highlighting
Merge pull request #194 from ulikoehler/master

Add README syntax highlighting
Fix typo in bin and readme
Added scenario in test case where properties shouldn't be accessed with
dotted syntax even with screw_ie8 option.
Signed-off-by: Justin Lau <justin@tclau.com>
Fixed dot property issue with invlid identifier names.
Signed-off-by: Justin Lau <justin@tclau.com>
Added test scenario with unicode in properties name.
Signed-off-by: Justin Lau <justin@tclau.com>
Fixed dot properties not optimizing unicode identifiers. Signed-off-by: Justin Lau <justin@tclau.com>
Merge pull request #195 from kjbekkelund/typo

Fix typo in bin and readme
Added test cases for #104.
Signed-off-by: Justin Lau <justin@tclau.com>
Fixed typeof undefined optimization and updated related test case to
accomodates the sort behaviour changes made in commit
mishoo/UglifyJS2@aebafad41eab48f43ed649ce8c77e8f1528b50da.
Signed-off-by: Justin Lau <justin@tclau.com>
Better fix for equality of typeof ... against "undefined"
v2.3.1
Fix property names

Close #199
add a test for zero-length string in is_identifier_string, which is used in property compression. Also added a test exercising the change.
Add CI build for supported Node versions
Add Travis build badge to README
Fix is_assignable

(not likely to be noticed, it's only used in `strict` parse mode)