Actualize Oracle SQL generator and Oracle datatypes

Original oracle SQL generation and data types support was non-functional (see #196). Here are fixes tested on Oracle 11g.

Supports:

quote identifiers with " if lower-case letters are present (such identifiers are treated as case-sensitive by Oracle)
fully upper-cased identifiers stay unquoted (and thus are treated as case-insensitive by Oracle)
generation of sequences for auto-incremented simple PK columns
generation of triggers which conditionally fill in PK columns from sequences if they are left NULL on insert
generation of commented block of DROP statements in the beginning - useful when re-creating DB schema
CREATE TABLE and COMMENT statements are laid out in padded columns - for better clarity
generation of dummy constraint names for unique indexes
generation of FK constraint names based on from- and to- table names concatenation (fitted into the limit of 30 chars per identifier that Oracle imposes)

Does not support:

several auto-incremented columns per one table (not tested, may not work as desired)
FKs on compound keys (seems there are several nodes in the input DB schema XML per such FKs: one per every column of compound key - this is pretty hard to merge into single ALTER TABLE statement with XSLT v1.0)
auto-incremented columns feature of Oracle 12c

ondras / wwwsqldesigner