Add support for character encoding configuration (Fixes #46)

[renanwilliam]

Summary

• Add support for separate Node.js and Java character encoding configuration
• Fixes issue with special characters (accents, cedillas, etc.) when connecting to databases using legacy encodings like Windows-1252
• Maintains 100% backward compatibility

Problem Solved

Resolves issue #46 where special characters are not handled correctly due to encoding mismatches between Java and Node.js components.

Changes Made

Core Implementation

• SybaseDB.js: Added optional javaEncoding parameter to constructor options
• Main.java: Added constructor overload to accept encoding parameter (preserves existing constructor)
• StdInputReader.java: Added constructor with encoding support, falls back to default on error
• Java Process: Automatically passes -Dfile.encoding JVM parameter when javaEncoding is specified

Testing & Documentation

• test_encoding.js: Comprehensive Mocha/Chai tests covering all encoding scenarios
• README.md: Complete documentation with usage examples and common encoding combinations
• JavaSybaseLink.jar: Recompiled with encoding support

New API Usage

var Sybase = require('sybase');
var db = new Sybase('host', port, 'dbName', 'username', 'password', false, null, {
    encoding: 'latin1',     // Node.js IPC encoding 
    javaEncoding: 'Cp1252', // Java database communication encoding
    extraLogs: false
});

// Now queries with special characters work correctly
db.query('SELECT * FROM usuarios WHERE nome = "José"', callback);

Common Use Cases

• Windows-1252 databases: encoding: 'latin1', javaEncoding: 'Cp1252'
• ISO-8859-1 databases: encoding: 'latin1', javaEncoding: 'ISO-8859-1'
• UTF-8 databases: No changes needed (default behavior)

Backward Compatibility

✅ All existing code continues to work without changes
✅ New parameters are optional
✅ Java constructors use method overloading (no breaking changes)
✅ Default behavior unchanged

Test Results

• ✅ 8 new tests passing (encoding functionality)
• ✅ All existing functionality preserved
• ✅ No breaking changes detected

🤖 Generated with Claude Code