csv2ddl: Also print a COPY FROM statement

input.Makefile: Fixed bug where input type was considered to be different things if both $(inputFiles) and $(dbExport) are non-empty. Now, $(inputFiles) takes precedence so that the presence of any input files will cause a DB dump to be ignored. This ensures that a (slower) input DB is not used over a (faster) flat file.

csvs.py: stream_info(): Added parse_header option. reader_and_header(): Use stream_info()'s new parse_header option.

csv2ddl: Renamed schema name env var from datasrc to schema to reflect what it is, and to make the script general beyond importing inputs

input.Makefile: Moved Installation, Staging tables after Existing maps discovery because they depend on it. Staging tables: Create a staging table for each table a map spreadsheet is available for. Put double quotes around the schema name so its case is preserved.

Added csv2ddl to make a PostgreSQL CREATE TABLE statement from a CSV header

sql.py: Input validation: Moved section after Database connections because some of its functions require a connection. Added esc_name_by_module() and esc_name_by_engine(), and use esc_name_by_module() in esc_name().

input.Makefile: Installation: Create a schema for the datasource in VegBIEN as part of the installation process. This will be used to hold staging tables.

input.Makefile: Changed install, uninstall to depend on src/install, src/uninstall targets, which in turn depend on db, rm_db. This will allow us to add additional install actions for all input types.

sql.py: DbConn: Cache the constructed CacheCursor itself, rather than the dict that's used to create it