Remove MapperFeature.USE_STD_BEAN_NAMING

[cowtowncoder]

This feature was added for backwards compatibility, to allow enabling of standard bean naming behavior for case of multiple leading upper-case characters. Canonical example is:

public URL getURL();

which according to Bean naming should NOT be modified -- that is, should infer property "URL" -- but that with Jackson 1.x and 2.x would by default be all lower-cased ("url").

We want to get things more compatible with standard behavior, so this feature effectively changes from default of false to true. But there seems to be little point in supporting older behavior: it is possible to get such behavior by either:

1. Annotating limited number of cases with @JsonProperty or
2. Writing/modifying one of PropertyNamingStrategy cases to handle these cases.

[cowtowncoder]

Fixed: FasterXML/jackson-databind#1772