Log Message:
Upadte ruby-pdf-reader to 1.4.0.

v1.4.0 (22nd February 2016)
- raise minimum ruby version to 1.9.3
- print warnings to stderr when deprecated methods are used. These methods have been
  deprecated for 4 years, so hopefully few people are depending on them
- Fix exception when a npn-breakng space (character 160) is used with a
  built-in fint (helvetica, etc)
- various bug fixes