Resolve issues from upstream repository

[crissdev]

Try to merge valid PRs from upstream repository and fix issues.

• Fix JSON string value of "constructor" throws exception on .fromJS call SteveSanderson/knockout.mapping#124 - Use hasOwnProperty to check for bucket existence 1cf041d (PR Use hasOwnProperty to check for bucket existence SteveSanderson/knockout.mapping#173)
• Put null check first in canHaveProperties 57a0b56 (PR Put null check first in canHaveProperties SteveSanderson/knockout.mapping#149)
• Use intermediate vars to decrease minified size f97d5cd (PR Use intermediate vars to decrease minified size SteveSanderson/knockout.mapping#151)
• Only get types once in mergeArrays e6c5631 (PR Only get types once in mergeArrays SteveSanderson/knockout.mapping#148)
• Incorrect handling of properties with periods (Incorrect handling of properties with periods (e.g. "foo.bar") SteveSanderson/knockout.mapping#96)
• allow JSON.stringify parameters to be specified to ko.mapping.toJSON 8e55292 (ko.mapping.toJSON to implement JSON formatting param like ko.toJSON SteveSanderson/knockout.mapping#205)
• include option is not working properly ('Include' option is not working properly SteveSanderson/knockout.mapping#176) - to verify
• Mapping doesn't work when properties listed in different order (Mapping doesn't work when properties listed in different order SteveSanderson/knockout.mapping#203)

[crissdev]

@tjyrkinen If time permits please take a look at SteveSanderson#176 (see above). It will help a lot in moving forward and getting close to v3.0. Thanks.