use Strings for record type instead of byte[]

This will allow for better comparison when processing records

    if (record.type === ndef.RTD_TEXT) {  /* blargh */ }

Instead of the old way where each element of the arrays needed to be compared
type is now string, no need to convert
decode uri record
add value property to ndef record with decoded payload for Text and URI records
Merge pull request #3 from don/string

Use Strings for record type instead of int[]