zxing 0.0.4

this plugin is a simple wrapper of native scanner for ios and zxing-android-embedded for android.

[0.0.1]

• this plugin is a simple wrapper of swiftScan for ios and zxing-android-embedded for android.

[0.0.4]

• Implement isContinuous parameters on ios platform.
• The swiftScan library is replaced with the system API.
• plugin returns a list of string rather than single string.